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multiple choice question! please help!
Suppose y varies directly with x, and y = 14 when x = –4. What is the value of y when x = –6?
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18
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 one year ago
 one year ago
multiple choice question! please help! Suppose y varies directly with x, and y = 14 when x = –4. What is the value of y when x = –6? –21 10 18 21
 one year ago
 one year ago

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jim_thompson5910Best ResponseYou've already chosen the best response.1
y varies directly with x means that y = kx
 one year ago

jim_thompson5910Best ResponseYou've already chosen the best response.1
when x = 4, y is y = 14 so y = kx turns into 14 = k*(4)
 one year ago

jim_thompson5910Best ResponseYou've already chosen the best response.1
solve for k and tell me what you get
 one year ago

lyzzy7Best ResponseYou've already chosen the best response.1
3.5, But I think Im wrong..
 one year ago

jim_thompson5910Best ResponseYou've already chosen the best response.1
you're correct
 one year ago

jim_thompson5910Best ResponseYou've already chosen the best response.1
so y = kx turns into y = 3.5x
 one year ago

jim_thompson5910Best ResponseYou've already chosen the best response.1
now they want to know the value of y when x = 6
 one year ago

jim_thompson5910Best ResponseYou've already chosen the best response.1
so y = 3.5x y = 3.5(6) y = ???
 one year ago

lyzzy7Best ResponseYou've already chosen the best response.1
can you walk me through this one too? Suppose y varies directly with x, and y = 25 when x = 140. What is the value of x when y = 36?
 one year ago

jim_thompson5910Best ResponseYou've already chosen the best response.1
y varies directly with x means what
 one year ago

jim_thompson5910Best ResponseYou've already chosen the best response.1
we're given x = 140 and y = 25 so y = kx becomes 25 = k*140
 one year ago

jim_thompson5910Best ResponseYou've already chosen the best response.1
I would use more decimal places for k. I'm going to use k = 0.17857 so y = kx becomes y = 0.17857x Now plug in y = 36 and solve for x y = 0.17857x 36 = 0.17857x 36/ 0.17857 = x 201.601613 = x x = 201.601613 now round to the nearest tenth to get 201.6 this is the same as 201 and 3/5 or the improper fraction 1008/5
 one year ago

jim_thompson5910Best ResponseYou've already chosen the best response.1
optionally... y = kx 25 = k*140 25/140 = k k = 25/140 k = 5/28  y = kx y = (5/28)x 36 = (5/28)*x 36*28 = 5x 1008 = 5x 5x = 1008 x = 1008/5 So x = 1008/5 which is x = 201.6 in decimal form
 one year ago
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